GD2 and GD3 gangliosides as diagnostic biomarkers for all stages and subtypes of epithelial ovarian cancer.

Background: Ovarian cancer (OC) is the deadliest gynecological cancer, often diagnosed at advanced stages. A fast and accurate diagnostic method for early-stage OC is needed. The tumor marker gangliosides, GD2 and GD3, exhibit properties that make them ideal potential diagnostic biomarkers, but they have never before been quantified in OC. We investigated the diagnostic utility of GD2 and GD3 for diagnosis of all subtypes and stages of OC. Methods: This retrospective study evaluated GD2 and GD3 expression in biobanked tissue and serum samples from patients with invasive epithelial OC, healthy donors, non-malignant gynecological conditions, and other cancers. GD2 and GD3 levels were evaluated in tissue samples by immunohistochemistry (n=299) and in two cohorts of serum samples by quantitative ELISA. A discovery cohort (n=379) showed feasibility of GD2 and GD3 quantitative ELISA for diagnosing OC, and a subsequent model cohort (n=200) was used to train and cross-validate a diagnostic model. Results: GD2 and GD3 were expressed in tissues of all OC subtypes and FIGO stages but not in surrounding healthy tissue or other controls. In serum, GD2 and GD3 were elevated in patients with OC. A diagnostic model that included serum levels of GD2+GD3+age was superior to the standard of care (CA125, p<0.001) in diagnosing OC and early-stage (I/II) OC. Conclusion: GD2 and GD3 expression was associated with high rates of selectivity and specificity for OC. A diagnostic model combining GD2 and GD3 quantification in serum had diagnostic power for all subtypes and all stages of OC, including early stage. Further research exploring the utility of GD2 and GD3 for diagnosis of OC is warranted.

Therapeutic Neuroprotection by an Engineered Neurotrophin that Selectively Activates Tropomyosin Receptor Kinase (Trk) Family Neurotrophin Receptors but Not the p75 Neurotrophin Receptor.

The neurotrophin growth factors bind and activate two types of cell surface receptors: the tropomyosin receptor kinase (Trk) family and p75. TrkA, TrkB, and TrkC are bound preferentially by nerve growth factor, brain-derived neurotrophic factor, and neurotrophin 3 (NT3), respectively, to activate neuroprotective signals. The p75 receptors are activated by all neurotrophins, and paradoxically in neurodegenerative disease p75 is upregulated and mediates neurotoxic signals. To test neuroprotection strategies, we engineered NT3 to broadly activate Trk receptors (mutant D) or to reduce p75 binding (mutant RK). We also combined these features in a molecule that activates TrkA, TrkB, and TrkC but has reduced p75 binding (mutant DRK). In neurodegenerative disease mouse models in vivo, the DRK protein is a superior therapeutic agent compared with mutant D, mutant RK, and wild-type neurotrophins and protects a broader range of stressed neurons. This work rationalizes a therapeutic strategy based on the biology of each type of receptor, avoiding activation of p75 toxicity while broadly activating neuroprotection in stressed neuronal populations expressing different Trk receptors. SIGNIFICANCE STATEMENT: The neurotrophins nerve growth factor, brain-derived neurotrophic factor, and neurotrophin 3 each can activate a tropomyosin receptor kinase (Trk) A, TrkB, or TrkC receptor, respectively, and all can activate a p75 receptor. Trks and p75 mediate opposite signals. We report the engineering of a protein that activates all Trks, combined with low p75 binding, as an effective therapeutic agent in vivo.

Inhibiting the MNK1/2-eIF4E axis impairs melanoma phenotype switching and potentiates antitumor immune responses.

Melanomas commonly undergo a phenotype switch, from a proliferative to an invasive state. Such tumor cell plasticity contributes to immunotherapy resistance; however, the mechanisms are not completely understood and thus are therapeutically unexploited. Using melanoma mouse models, we demonstrated that blocking the MNK1/2-eIF4E axis inhibited melanoma phenotype switching and sensitized melanoma to anti-PD-1 immunotherapy. We showed that phospho-eIF4E-deficient murine melanomas expressed high levels of melanocytic antigens, with similar results verified in patient melanomas. Mechanistically, we identified phospho-eIF4E-mediated translational control of NGFR, a critical effector of phenotype switching. Genetic ablation of phospho-eIF4E reprogrammed the immunosuppressive microenvironment, exemplified by lowered production of inflammatory factors, decreased PD-L1 expression on dendritic cells and myeloid-derived suppressor cells, and increased CD8+ T cell infiltrates. Finally, dual blockade of the MNK1/2-eIF4E axis and the PD-1/PD-L1 immune checkpoint demonstrated efficacy in multiple melanoma models regardless of their genomic classification. An increase in the presence of intratumoral stem-like TCF1+PD-1+CD8+ T cells, a characteristic essential for durable antitumor immunity, was detected in mice given a MNK1/2 inhibitor and anti-PD-1 therapy. Using MNK1/2 inhibitors to repress phospho-eIF4E thus offers a strategy to inhibit melanoma plasticity and improve response to anti-PD-1 immunotherapy.

Alternative Splicing of a Receptor Intracellular Domain Yields Different Ectodomain Conformations, Enabling Isoform-Selective Functional Ligands.

Events at a receptor ectodomain affect the intracellular domain conformation, activating signal transduction (out-to-in conformational effects). We investigated the reverse direction (in-to-out) where the intracellular domain may impact on ectodomain conformation. The primary sequences of naturally occurring TrkC receptor isoforms (TrkC-FL and TrkC.T1) only differ at the intracellular domain. However, owing to their differential association with Protein Disulfide Isomerase the isoforms have different disulfide bonding and conformations at the ectodomain. Conformations were exploited to develop artificial ligands, mAbs, and small molecules, with isoform-specific binding and biased activation. Consistent, the physiological ligands NT-3 and PTP-sigma bind both isoforms, but NT-3 activates all signaling pathways, whereas PTP-sigma activates biased signals. Our data support an "in-to-out" model controlling receptor ectodomain conformation, a strategy that enables heterogeneity in receptors, ligands, and bioactivity. These concepts may be extended to the many wild-type or oncogenic receptors with known isoforms.

Antagonism of proNGF or its receptor p75NTR reverses remodelling and improves bladder function in a mouse model of diabetic voiding dysfunction.

AIMS/HYPOTHESIS: Although 80% of diabetic patients will suffer from voiding difficulties and urinary symptoms, defined as diabetic voiding dysfunction (DVD), therapeutic targets and treatment options are limited. We hypothesise that the blockade of the pro-nerve growth factor (NGF)/p75 neurotrophin receptor (p75NTR) axis by an anti-proNGF monoclonal antibody or by a small molecule p75NTR antagonist (THX-B) can restore bladder remodelling (represented by bladder weight) in an animal model of DVD. Secondary outcomes of the study include improvements in bladder compliance, contractility and morphology, as well as in voiding behaviour, proNGF/NGF balance and TNF-α expression. METHODS: In a streptozotocin-induced mouse model of diabetes, diabetic mice received either a blocking anti-proNGF monoclonal antibody or a p75NTR antagonist small molecule as weekly systemic injections for 4 weeks. Animals were tested at baseline (at 2 weeks of diabetes induction), and after 2 and 4 weeks of treatment. Outcomes measured were voiding function with voiding spot assays and cystometry. Bladders were assessed by histological, contractility and protein expression assays. RESULTS: Diabetic mice showed features of DVD as early as 2 weeks after diabetes diagnosis (baseline) presented by hypertrophy, reduced contractility and abnormal cystometric parameters. Following treatment initiation, a twofold increase (p < 0.05) in untreated diabetic mouse bladder weight and thickness compared with non-diabetic controls was observed, and this change was reversed by p75NTR antagonism (37% reduction in bladder weight compared with untreated diabetic mice [95% CI 14%, 60%]) after 4 weeks of treatment. However, blocking proNGF did not help to reverse bladder hypertrophy. While diabetic mice had significantly worse cystometric parameters and contractile responses than non-diabetic controls, proNGF antagonism normalised bladder compliance (0.007 [Q1-Q3; 0.006-0.009] vs 0.015 [Q1-Q3; 0.014-0.029] ml/cmH2O in untreated diabetic mice, representing 62% reduction [95% CI 8%, 110%], p < 0.05) and contractility to KCl, carbachol and electrical field stimulation (p < 0.05 compared with the diabetic group) after 2 weeks of treatment. These effects were not observed after 4 weeks of treatment with proNGF antagonist. p75NTR antagonism did not show important improvements in cystometric parameters after 2 weeks of treatment. Slightly improved bladder compliance (0.01 [Q1-Q3; 0.009-0.012] vs 0.013 [Q1-Q3; 0.011-0.016] ml/cmH2O for untreated diabetic mice) was seen in the p75NTR antagonist-treated group after 4 weeks of treatment with significantly stabilised contractile responses to KCl, carbachol and electric field stimulation (p < 0.05 for each) compared with diabetic mice. Bladder dysfunction observed in diabetic mice was associated with a significant increase in bladder proNGF/NGF ratio (3.1 [±1.2] vs 0.26 [±0.04] ng/pg in control group, p < 0.05 at week 2 of treatment) and TNF-α (p < 0.05). The proNGF/NGF ratio was partially reduced (about 60% reduction) with both treatments (1.03 [±0.6] ng/pg for proNGF antibody-treated group and 1.4 [±0.76] ng/pg for p75NTR blocker-treated group after 2 weeks of treatment), concomitant with a significant decrease in the bladder levels of TNF-α (p < 0.05), despite persistent hyperglycaemia. CONCLUSIONS/INTERPRETATION: Our findings indicate that blockade of proNGF and the p75NTR receptor in diabetes can impede the development and progression of DVD. The reported improvements in morphological and functional features in our DVD model validates the proNGF/p75NTR axis as a potential therapeutic target in this pathology. Graphical abstract.

[New mutations associated with Hirschsprung disease]. / Nuevas mutaciones asociadas a la enfermedad de Hirschsprung.

INTRODUCTION: Hirschsprung disease is caused by an impairment in cell migration from the neural crest to the gastrointestinal tract, resulting in an absence of neurons in the myenteric plexus. Many mutations in several genes have been associated to Hirschsprung disease; most of them affecting the RET proto-oncogen pathway. The purpose of this study is the description of novel and known mutations in genes associated to Hirschsprung disease and their prognostic implications. MATERIAL AND METHODS: Retrospective analysis of patients with Hirschsprung disease and positive genetic studies evaluated from 1970 to 2013. RESULTS: We found 21 positive genetic studies in the global series, 17 of them involving the RET proto-oncogene. Two of the mutations are novel and they have not been reported in the medical literature. CONCLUSIONS: The RET protooncogene is the main gene associated with Hirschsprung disease. There are still multiple unknown mutations related to the pathogenesis of the disease. The study of this gene must be part of the work-up of all patients with Hirschsprung disease, as well as their first degree relatives if the mutation is associated with MEN2A and MEN2B syndromes.

New mutations associated with Hirschsprung disease.

INTRODUCTION: Hirschsprung Disease is caused by an impairment in cell migration from the neural crest to the gastrointestinal tract, resulting in an absence of neurons in the myenteric plexus. Many mutations in several genes have been associated to Hirschsprung disease; most of them affecting the RET proto-oncogen pathway. The purpose of this study is the description of novel and known mutations in genes associated to Hirschsprung disease and their prognostic implications. MATERIAL AND METHODS: Retrospective analysis of patients with Hirschsprung disease and positive genetic studies evaluated from 1970 to 2013. RESULTS: We found 21 positive genetic studies in the global series, 17 of them involving the RET proto-oncogene: Two of the mutations are novel and they have not been reported in the medical literature. CONCLUSIONS: The RET protooncogene is the main gene associated with Hirschsprung disease. There are still multiple unknown mutations related to the pathogenesis of the disease. The study of this gene must be part of the work-up of all patients with Hirschsprung disease, as well as their first degree relatives if the mutation is associated with MEN2A and MEN2B syndromes.

Neuroprotection: Pro-survival and Anti-neurotoxic Mechanisms as Therapeutic Strategies in Neurodegeneration.

Neurotrophins (NTs) are a subset of the neurotrophic factor family. These growth factors were originally named based on the nerve growth functional assays used to identify them. NTs act as paracrine or autocrine factors for cells expressing NT receptors. The receptors and their function have been studied primarily in cells of the nervous system, but are also present in the cardiovascular, endocrine, and immune systems, as well as in many neoplastic cells. The signals activated by NTs can be varied, depending on cellular stage and context, healthy or disease states, and depending on whether the specific NTs and their receptors are expressed in the relevant cells. In the healthy central and peripheral adult nervous systems, NTs drive neuronal survival, phenotype, synaptic maintenance, and function. Deficiencies of the NT/NT receptor axis are causally associated with disease onset or disease progression. Paradoxically, NTs can also drive synaptic loss and neuronal death. In the embryonic stage this activity is essential for proper developmental pruning of the nervous system, but in the adult it can be associated with neurodegenerative disease. Given their key role in neuronal survival and death, NTs and NT receptors have long been considered therapeutic targets to achieve neuroprotection. The first neuroprotective approaches consisted of enhancing neuronal survival signals using NTs. Later strategies selectively targeted receptors to induce survival signals specifically, while avoiding activation of death signals. Recently, the concept of selectively targeting receptors to reduce neuronal death signals has emerged. Here, we review the rationale of each neuroprotective strategy with respect to the complex cell biology and pharmacology of each target receptor.

Vaccination with Tumor-Ganglioside Glycomimetics Activates a Selective Immunity that Affords Cancer Therapy.

Immune targeting of (glyco)protein tumor markers has been useful to develop cancer and virus vaccines. However, the ganglioside family of tumor-associated glycolipids remains intractable to vaccine approaches. Here we show that synthetic antigens mimicking the carbohydrate moiety of GD2 or GD3 gangliosides can be used as vaccines to activate a selective humoral and cellular immunity that is therapeutic against several cancers expressing GD2 or GD3. Adoptive transfer of T cells generated after vaccination elicits tumor-infiltrating lymphocytes of the γδ T cell receptor and CD8+ phenotypes; and affords a high therapeutic index. The glycomimetic vaccine principles can be expanded to target the family of tumor gangliosides and other carbohydrates expressed primarily in pathological states.

Is Intraoperative Fluoroscopy Necessary for Central Venous Port System Placement in Children?

INTRODUCTION: Central venous port (CVP) placement is traditionally performed under fluoroscopy guidance. However, efforts for radiation dose reduction in children have allowed the introduction of ultrasound guidance (USG) and anatomic landmarks as an alternative technique for CVP placement. The aim of this study is to determine whether intraoperative fluoroscopy (IF) is required to confirm the correct position of the catheter tip in children. PATIENTS AND METHODS: A prospective, single-center study was performed between July and December 2017. Standard venous access site was the right internal jugular vein under USG. Estimated catheter length (ECL) was measured using anatomic landmarks. Ideal catheter length (ICL) was measured after placement under fluoroscopy guidance in the same patient. Age, sex, radiation dose, and complications were also analyzed. A t-test for paired samples and intraclass correlation coefficient were performed to analyze results. RESULTS: A total of 30 consecutive patients aged 7 ± 2 years underwent CVP placement. The mean ECL was 17.1 ± 1.8 cm, while the mean ICL was 17.7 ± 1.8 cm. The mean difference between measurements was 0.28 cm (95% confidence interval [CI], -0.29 to 0.86; p = 0.324). Intraclass correlation coefficient analysis showed an agreement of 0.95 (95% CI, 0.91-0.98) between measurements. Mean radiation exposure during the procedure was 1.060.78 mGym2 during 0.34 ± 0.6 minutes. There were no complications registered during CVP placement. CONCLUSION: The correlation between IF and USG and anatomically guided catheter tip placement is optimal. These results suggest that fluoroscopy and the radiation exposure it entails can be safely avoided in selected children.

Long-Term Results after Diversion Surgery in Extrahepatic Portal Vein Obstruction.

AIM: Extrahepatic portal vein obstruction (EHPVO) is a frequent cause of noncirrhotic portal hypertension in children. The aim of this study is to analyze long-term results after diversion surgery. PATIENTS AND METHODS: Retrospective review of EHPVO patients who underwent diversion surgery analyzing number of platelets, leukocytes, prothrombin activity, splenomegaly, and gastrointestinal bleeding 10 years after surgery. RESULTS: Thirty-three patients were evaluated, mostly males (64%) and presenting with gastrointestinal bleeding (46%). Mesoportal shunt (Rex) was performed in 19 patients, mesocaval in 7, distal splenorenal in 7, and proximal splenorenal in 3. While comparing mesoportal shunt to the other portosystemic shunts, an increase in platelets was found with every technique, but it was clearly higher in mesoportal shunt. The highest increase was 6 months after surgery (p = 0.0015) as well as prothrombin activity (p = 0.0003). Leukocytes level also increased without statistical significance. Spleen size (cm) and spleen size Z score (SSAZ) decreased significantly 6 months after mesoportal shunt (p = 0.0168). Before surgery, over 94% patients suffered gastrointestinal bleeding, which reduced significantly afterward with bleeding episodes in only four (12%) of them. CONCLUSION: Diversion surgery in EHPVO, especially mesoportal shunt of Rex, improves hepatic function (prothrombin activity), reduces hypersplenism (platelets, leukocytes, and spleen size), and decreases gastrointestinal bleeding episodes.

Prognostic Factors for Liver Transplantation in Unresectable Hepatoblastoma.

AIM: Hepatoblastoma is the most frequent hepatic tumor in children, and its initial presentation will affect treatment and prognosis. The aim of this study is to evaluate long-term results of liver transplantation in children with unresectable hepatoblastoma. PATIENTS AND METHODS: This is a retrospective review of patients with hepatoblastoma who underwent liver transplantation, analyzing risk factors, tumor presentation, treatment, and long-term survival to identify prognostic factors. RESULTS: Thirty-one patients underwent liver transplantation in the context of unresectable hepatoblastoma, mainly males (67%) and with risk factors such as prematurity (12.9%), maternal smoking (6.5%), and familial adenomatous polyposis (3.2%). Most frequent presentation was multifocal PRETEXT III (51.6%) and PRETEXT IV (45.2%), with metastasis at diagnosis in 12.9% and vascular involvement in 54.8%.Twenty-one patients received a living-donor (67.7%) and 10 a cadaveric graft (32.2%), at 31.7 months of age (5-125). Most transplants were primary, and only two were performed as rescue therapy after an attempt of surgical resection of the tumor.Overall survival 1 and 5 years after transplantation were 93.3% ± 4.6% and 86.4% ± 6.3%, respectively. We could not find any statistically significant differences between risk factors, tumor presentation, type of graft, or type of transplant. CONCLUSION: Liver transplantation has increased hepatoblastoma survival in unresectable tumors. Probably due to these good results, we have not been able to find significant prognostic factors in this cohort.

Using Tissue Expanders as a Choice for the Treatment of Congenital Facial Nevus in the Young Child.

OBJECTIVE: One of the principal objectives in treatment of facial nevus is to minimize psychological damage and encourage the child's schooling by the best possible cosmetic result. There are several therapeutic techniques: grafts, flaps, dermal regenerator, and tissue expanders. MATERIALS AND METHODS: We reviewed 10 patients with facial nevus higher than 10 cm treated in the past 8 years. Our treatment protocol includes serial expander implant to remove everything that does not involve the eyelid and nasal pyramid. Ten patients were included, between 8 and 36 months of age. A median of 4 (2-6) surgeries were conducted, and the number of implanted expanders was 1 to 3 in each session. There were only minor complications in two patients, infection that responded to antibiotic therapy and minimal dehiscence of incision forcing resuturing. The median follow-up was 1.6 (1.3-3.4) years. CONCLUSION: Tissue expansion has become in recent years the treatment of choice for facial nevus in children, obtaining the best aesthetic result because the defect is covered with similar characteristics in color, texture, and relief skin. It is essential that the reconstruction is done by specialized units and we recommend complete surgical excision before starting school.

Pitfalls in Diagnosis of Early-Onset Inflammatory Bowel Disease.

AIM: The onset of inflammatory bowel disease (IBD) in patients younger than the age of 5 years is rare. Moreover, when there is exclusive colonic inflammation, diagnosis can be challenging. Our aim was to describe the difficulties and pitfalls in the diagnosis of early-onset IBD (eoIBD) and their repercussions in treatment decisions. PATIENTS AND METHODS: Patients with eoIBD (Crohn's disease [CD], ulcerative, and unclassified colitis) treated at our center between 1990 and 2016 were studied retrospectively. Demographic, clinical, medical, and surgical treatment data were analyzed. RESULTS: A total of 19 patients were diagnosed with eoIBD at 21 (1-46) months of age. Bloody diarrhea, growth failure, and abdominal pain were present in 90, 42, and 16%, respectively. After 9 (1-62) months from the onset, patients were classified as ulcerative colitis (nine), CD (two), and unclassified colitis (eight). Unresponsiveness to medical treatment was observed in 10 and prompted surgical assessment. A partial colectomy was performed in one, and nine underwent a total colectomy (one end stoma and eight ileoanal anastomosis [IAA]). At least one surgical complication occurred in 80% and ultimately six patients with an IAA required an end stoma. Overtime, final diagnosis of 5 out of the 10 surgical patients changed due to biopsy findings, unresponsiveness to medical treatment, or extraintestinal and perianal manifestations. After a 12-year (1-22) follow-up, 57.9% of the diagnoses of all patients were modified. CONCLUSION: EoIBD poses a challenge due to ambiguous presentation and absence of specific diagnostic tests. Surgical evaluation is often needed and surgeons must be mindful of possible initial misdiagnosis, in addition to short- and long-term outcomes before deciding aggressive surgical measures as well as intestinal reconstruction.

In retinitis pigmentosa TrkC.T1-dependent vectorial Erk activity upregulates glial TNF-α, causing selective neuronal death.

In some diseases the TrkC.T1 isoform is upregulated in glia, associated with glial TNF-α production and neuronal death. What remains unknown are the activating signals in glia, and how paracrine signals may be selective for a targeted neuron while sparing other proximate neurons. We studied these questions in the retina, where Müller glia contacts photoreceptors on one side and retinal ganglion cells on the other. In a mutant Rhodopsin mouse model of retinitis pigmentosa (RP) causing progressive photoreceptor death-but sparing retinal ganglion cells-TrkC.T1 and NT-3 ligand are upregulated in Müller glia. TrkC.T1 activity generates p-Erk, which causes increased TNF-α. These sequential events take place predominantly in Müller fibers contacting stressed photoreceptors, and culminate in selective death. Each event and photoreceptor death can be prevented by reduction of TrkC.T1 expression, by pharmacological antagonism of TrkC or by pharmacological inhibition Erk. Unmasking the sequence of non-cell autologous events and mechanisms causing selective neuronal death may help rationalize therapies.

Ultrashort Bowel Syndrome Outcome in Children Treated in a Multidisciplinary Intestinal Rehabilitation Unit.

Aim Short bowel syndrome (SBS) is the leading cause of intestinal failure (IF) in the pediatric population. Our aim was to review long-term outcome of ultrashort bowel syndrome (USBS) in an Intestinal Rehabilitation Unit (IRU). Patients and Methods Retrospective study of patients with USBS (defined as < 10 cm of remnant small bowel) treated between 2000 and 2015. Demographic data, clinical, and treatment variables including parenteral nutrition (PN), surgical techniques, and intestinal transplantation (IT) were analyzed. Results Out of 250 children, 30 referred to the IRU met inclusion criteria. Upon first assessment, patients had a median age of 3 (1-217) months and had undergone 3 (1-6) previous laparotomies that left 5 (0-9) cm of remnant small bowel. The main cause of USBS was neonatal midgut volvulus (50%). Follow-up was 28 (4-175) months. Advanced IF-associated liver disease (IFALD) was documented in 63%. None of the patients achieved digestive autonomy and was consequently considered for IT. One patient was excluded, five died before IT, and three are still on the waiting list. Six patients received an isolated IT, 6 a combined liver IT, and 18 a multivisceral graft. Digestive autonomy was achieved in 71% after 31 (14-715) days after IT and currently 62% are alive and off total PN. A significant drop in IFALD progression prior to IT was observed with the introduction of new lipid emulsions in 2010 (SMOF or Soy oil MCT (mid-chain triglycerides) Olive oil Fish oil). Conclusion A multidisciplinary IRU including an IT program offers a comprehensive approach for patients with IF and is crucial to improve survival rate of USBS. New PN lipid emulsions had an impact on IFALD progression and may eventually reduce overall mortality.

Hepatocellular Carcinoma: Referral to a Transplantation Unit.

Aim Hepatocellular carcinoma (HCC), although being infrequent, is the second-most common primary hepatic malignancy in children, after hepatoblastoma (HB). The prognosis is very poor. We present our series of children with HCC referred to our transplant unit to be assessed as candidates for liver transplantation (LT). Methods A retrospective review of HCCs referred to our transplant unit in the past 20 years (1994-2015) was performed. Age at diagnosis, disease-free survival, location of recurrence, initial treatment, secondary treatment, and mortality were noted. Main Results Ten patients (8 boys, 2 girls) met the inclusion criteria. Median age at diagnosis was 11.5 years (0.5-14). HCC was associated with tyrosinemia in two patients, while the tumor developed in absence of previous liver disease in eight. Seven children attempted tumor resection earlier elsewhere. LT was not considered suitable in six patients due to extrahepatic tumor extension and finally it was performed in four (two with tyrosinemia and two with "de novo" HCC). Only one of the transplants was primary, and the other three were performed as rescue therapy. After 78 (66-90) months of follow-up, the two patients with tyrosinemia remain alive and disease free, while the other two had distant relapses, 35 and 37 months after LT, respectively, and finally died due to tumor progression. Conclusions HCC is a rare, very aggressive tumor in children who has a very poor prognosis. Our results suggest the need for new strategies. Early referral of all cases to highly specialized centers with a liver transplant unit and perhaps a more liberal use of LT, even for selected, apparently resectable cases, are possible options.

The Paradoxical Signals of Two TrkC Receptor Isoforms Supports a Rationale for Novel Therapeutic Strategies in ALS.

Full length TrkC (TrkC-FL) is a receptor tyrosine kinase whose mRNA can be spliced to a truncated TrkC.T1 isoform lacking the kinase domain. Neurotrophin-3 (NT-3) activates TrkC-FL to maintain motor neuron health and function and TrkC.T1 to produce neurotoxic TNF-α; hence resulting in opposing pathways. In mouse and human ALS spinal cord, the reduction of miR-128 that destabilizes TrkC.T1 mRNA results in up-regulated TrkC.T1 and TNF-α in astrocytes. We exploited conformational differences to develop an agonistic mAb 2B7 that selectively activates TrkC-FL, to circumvent TrkC.T1 activation. In mouse ALS, 2B7 activates spinal cord TrkC-FL signals, improves spinal cord motor neuron phenotype and function, and significantly prolongs life-span. Our results elucidate biological paradoxes of receptor isoforms and their role in disease progression, validate the concept of selectively targeting conformational epitopes in naturally occurring isoforms, and may guide the development of pro-neuroprotective (TrkC-FL) and anti-neurotoxic (TrkC.T1) therapeutic strategies.

p75NTR and Its Ligand ProNGF Activate Paracrine Mechanisms Etiological to the Vascular, Inflammatory, and Neurodegenerative Pathologies of Diabetic Retinopathy.

UNLABELLED: In many diseases, expression and ligand-dependent activity of the p75(NTR) receptor can promote pericyte and vascular dysfunction, inflammation, glial activation, and neurodegeneration. Diabetic retinopathy (DR) is characterized by all of these pathological events. However, the mechanisms by which p75(NTR) may be implicated at each stage of DR pathology remain poorly understood. Using a streptozotocin mouse model of diabetic retinopathy, we report that p75(NTR) is upregulated very early in glia and in pericytes to mediate ligand-dependent induction of inflammatory cytokines, disruption of the neuro-glia-vascular unit, promotion of blood-retina barrier breakdown, edema, and neuronal death. In a mouse model of oxygen-induced retinopathy, mimicking proliferative DR, p75(NTR)-dependent inflammation leads to ischemia and pathological angiogenesis through Semaphorin 3A. The acute use of antagonists of p75(NTR) or antagonists of the ligand proNGF suppresses each distinct phase of pathology, ameliorate disease, and prevent disease progression. Thus, our study documents novel disease mechanisms and validates druggable targets for diabetic retinopathy. SIGNIFICANCE STATEMENT: Diabetic retinopathy (DR) affects an estimated 250 million people and has no effective treatment. Stages of progression comprise pericyte/vascular dysfunction, inflammation, glial activation, and neurodegeneration. The pathophysiology of each stage remains unclear. We postulated that the activity of p75NTR may be implicated. We show that p75NTR in glia and in pericytes mediate ligand-dependent induction of inflammatory cytokines, disruption of the neuro-glia-vascular unit, promotion of blood-retina barrier breakdown, edema, and neuronal death. p75NTR-promoted inflammation leads to ischemia and angiogenesis through Semaphorin 3A. Antagonists of p75NTR or antagonists of proNGF suppress each distinct phase of pathology, ameliorate disease, and prevent disease progression. Our study documents novel mechanisms in a pervasive disease and validates druggable targets for treatment.